The influence of thin films on the surface of a dielectric on the spectrum and energy of surface waves in transitional radiation from relativistic charged particles

The study focuses on the excitation of surface electric waves (SEW) by a charged particle incident on the surface of a dielectric at a small angle. The fields and energy of SEW are defined. It is shown that the contact of a dielectric medium with a surface whose permittivity is less than -1 leads to a spectral shift of the critical frequency of SEW excitation. By varying the thickness and permittivity of the film the critical frequency of the SEW spectrum can be shifted into the long-wave region; for silver, under certain conditions, a shift from 3350 to 5000 A can be obtained.